Not Applicable.
Not Applicable.
The invention relates to ergonomic support members for the wrist or lower arm. While the invention will find particular application to use by those manipulating or entering data on computers, it is also useful in any environment wherein a user must perform repetitive hand actions where numerous movements of the hand(s) are required, especially when the hands are disposed forwardly in front of from the body. For example, many light assembly jobs involve repetitive tasks with the user""s hands disposed in front of the body. In such environments, repetitive strain injuries occur when the same motion is repeated hundreds or thousands of times each day. While there are many possible causes of a particular person""s malady, one form is often occasioned when the worker repeatedly pronates the wrists and hands, or maintains them in a (relatively) pronated position.
It is to be understood that the invention will be primarily described in the environment of a computer user; however, the beneficial use of the present invention should not be considered so limited. The present invention may be used in any number of different office or industrial environments, such as 10-key adding machines, controllers of factory machinery, and the like.
Incorrect hand and wrist posture increases the likelihood and severity of repetitive strain injuries. Movements of the wrist such as flexion, extension, abduction, and adduction cause the tendons to be displaced past and against adjacent anatomic surfaces, which causes repetitive strain injuries. Use of a computer keyboard or mouse places the hand and wrist (the xe2x80x9clower armxe2x80x9d) in a potentially unnatural position, wherein the wrist may be flexed or deviated side to side, and fingers may be strained. Redesign of the keyboard or mouse can be beneficial, but furthermore, not all users are in the at-risk group or willing to pay the higher cost of ergonomically redesigned components. Therefore, in addition to redesigning data input devices, a device is desired that can be used in conjunction with a conventional data input device such as a computer mouse or keyboard. While relieving the physical strains encountered by some users, is desirable. Such devices will preferably reduce fatigue and increase comfort, thereby increasing productivity and job satisfaction.
The cost of repetitive strain injuries, such as Carpal Tunnel Syndrome, is enormous, not only in medical claims but in lost time and retraining expenses. To a large extent, such injuries are often preventable if correct arm/wrist/hand posture is maintained by the worker. It is believed that a large portion of such injuries are at least in part the result of prolonged flexing and relative xe2x80x9cpronationxe2x80x9d of the worker""s wrists--that is, with the hands held in front of the body, rotation of the wrists such that the thumbs rotate downwardly and the palms face downwardly toward the floor. Conversely, with the thumbs rotated relatively upwardly from a horizontal plane, and the palms slightly inwardly, the hands/wrists are relatively more xe2x80x9csupinatedxe2x80x9d, a more ergonomically pleasing position that relieves stress to tendons, ligaments and other anatomical structures, and is therefore less likely to result in repetitive stress injuries.
The prior art devices have fallen into two broad categories: devices upon which the wrist or butt of the hand is rested while typing at a computer keyboard, or devices used in conjunction with computer mice to support the palm or wrist of the user. Wrist and arm supports have been developed that consist of an elongated pad typically positioned along and adjacent to the front of, for example, a keyboard. Such rests help to relieve posture and stress related injuries of keyboard users by supporting the wrist in a fixed position relative to the hand and arm so that the degree of bending at the wrist is decreased, this decreasing the stress caused by repetitive motion.
Such devices have been used with trackballs, joysticks, pens, and pointing devices, which vary relative to their shape, ergonomics and the means of converting tracking movement of the device to movement of a cursor on a computer screen. These characteristics determine the amount of space needed to use the pointing device, the intuitiveness of the device, as well as the time required to perform a pointing task. Greater intuitiveness in directing a cursor motion via the manipulation of a pointing device can decrease the time to achieve a comfortable skill level with an unfamiliar pointing device and can result in quicker target acquisition speed. The increasing use of graphical user interfaces such as Microsoft Windows (TM) has resulted in a dramatic increase in the utilization of computer pointing devices, with a consequent increase in repetitive strain injuries associated therewith.
More information about this syndrome is available in xe2x80x9cThe Handling of an Epidemic,xe2x80x9d published in Working Woman, February 1993, pp. 60-65, which is hereby incorporated by reference. For information on ergonomics in the workplace, see xe2x80x9cVideo Display Terminal Ergonomics,xe2x80x9d published in Professional Safety, June 1992, pp. 32-39, which is also incorporated herein by reference.
The prior art illustrates a number of approaches to solving the problem of repetitive strain injuries. U.S. Pat. No. 5,340,067 discloses an apparatus for retaining a computer mouse securely within the device, which is molded to fit the user""s fingers, palm and wrist. Likewise U.S. Pat. No. 5,562,270 discloses a wrist support for use with both a computer keyboard or mouse. When used with a mouse, the mouse is manipulated on a base member of the device while the wrist of the user rests on a pedestal.
U.S. Pat. No. 5,398,896 discloses an apparatus for use in conjunction with a computer keyboard, wherein the palms of the user""s hands rest in supports which travel across the computer keyboard. Likewise, U.S. Pat. No. 5,203,527 discloses a stationary wrist rest device positioned across the base of the entire keyboard upon which a typist can rest his/her wrists during use of the keyboard. U.S. Pat. No. 5,131,614 discloses a wrist support for alleviating strain from use of a mouse, comprising a pad extending along the front of a keyboard upon which travels the mouse.
U.S. Pat. No. 5,131,614 discloses a wrist support for alleviating some of the posture and stress related problems associated with the use of computer mice. The wrist support comprises a longitudinal pad in front of the keyboard and base that rests on a desk or other support surface. U.S. Pat. No. 5,433,407, commonly owned, discloses a cantilevered palm rest having a hand support section, a platform section and a connector to the base. A space is provided between the palm rest and the base so that a mouse or pointing device can be positioned therebetween during use.
However, none of the prior art devices provides the user with the effect of an internal dynamic suspension that increases the uniformity of support throughout the expected range of use-any relative movement between the hand and device is effected by the hand alone.
A device capable of dynamically following the working motions of the lower arm would alleviate stress placed on the lower arm and would result in less fatigue and fewer injuries. Additionally, such device would support the user""s hand and follow the natural movement of the hand and fingers as they flex, extend, contract, etc. in order to manipulate a work piece. For example, when using pointing devices: as the pointer is moved away from the body, the hand tends to flatten and the fingers move down relative to the wrist, which moves up relative to the fingers; as the pointer is moved toward the body, the hand tends to ball up, with the fingers moving up relative to the wrist and the wrist moving down relative to the fingers. Repeated movement of the fingers and wrist in this fashion results in a forward-to-rearward rocking of the hand. If the palm, palm/wrist or palm/wrist/arm rest is not capable of dynamic movement in response to this hand movement, then greater strain of the movement is born by the hand, more particularly by the wrist, and access to the pointing device is diminished.
In response to these observations, the present invention may be used in conjunction both with devices for data entry into, or pointing devices used with, for example, computers, or with other industrial processes or using a writing instrument such as a pen. There is a need for a device which ergonomically supports the user""s hand or wrist and retains a work piece (a mouse, pointer, 10-key adding machine, etc) to be manipulated by the user""s hand. Such device should permit a normal rocking motion of the hand and wrist, while at the same time providing sufficient lateral support to the user""s hand and/or wrist that undesired flexing and pronation of the wrist is reduced or eliminated.
The invention is an apparatus for reducing or eliminating the repetitive stress injuries commonly experienced in many office or industrial environments, especially (but not exclusively) in conjunction with computer data entry or pointing devices. The apparatus of the present invention comprises, in its broadest embodiment, an ergonomic lower arm suspension enabling a user to effect forward and rearward rocking motion of the hand when engaged with the apparatus. The lower arm suspension may be considered as an entity independent of means of relating to a workplace or cofunctional components or work pieces. As an application of the invention and as a means of describing its application, the lower arm suspension may have a xe2x80x9csupport base memberxe2x80x9d herein understood to be the component supporting the lower arm suspension, and can be, for example, a planar base upon which rests a computer pointing device such as a mouse, or it may be a sork space containing articles to be manipulated by the user. The support base may be merged with the lower arm suspension, or they may be connected by a connecting portion that may or may not contribute to the dynamics of the lower arm suspension. It is to be understood that in the context of this invention, the phrase xe2x80x9clower armxe2x80x9d is to be read to include the forearm, the wrist and the hand, either singly or in combination. That is, the device in its broadest embodiment may be constructed to support just the palm of the hand, the wrist and hand, or the forearm, wrist and hand. The drawings herein are intended to represent any of these embodiments even though they may not illustrate each individually.
The lower arm support suspension is constructed in a manner that enables relative supination of the lower arm while inhibiting relative pronation of the lower arm (as defined above).
In one embodiment of the invention there is provided a connecting portion comprising one or a plurality of tensioned members affixed to a rearward portion of the support member, biased upwardly and forwardly so as to create a space to permit work pieces to be disposed therebetween. The forward-tensioning of the connecting portion permits the spring action necessary to permit the forward-rearward rocking action. A preferred embodiment comprises three tensioned members, with the heel of the hand fitting between a first pair of the members, and the base of the thumb positioned on an opposite side of the device between a second pair of the members. In an additional embodiment of the invention, the connecting portion comprises a single tensioned member supporting a contoured rigidly deformable foam support apparatus. In another embodiment the base may be mobile by sliding on a working surface or by other means of relative mobility as on rails, tracks, wheels or other means of mobility.
In a still further embodiment, either a fixed or mobile lower arm suspension may be integrated into the work piece with no intermediate connecting portion, with a rigid connecting portion, with an adjustable connecting portion, or with a flexibly connected portion.
Accordingly, it is an object of the present invention to provide an apparatus effective in eliminating the repetitive stress injuries commonly associated with many office or industrial jobs. The inventive features of the invention will be set forth in greater detail below.